On Wed, 21 Nov 2007, Mathieu Desnoyers wrote:

> return -ENOENT;
> 
> directly ?
> 
> (ERR_PTR() in linux/err.h is a simple cast from long to void*).

Right and there is also IS_ERR_VALUE. Thanks for the feedback. New 
version:


Modules: Handle symbols that have a zero value

The module subsystem cannot handle symbols that are zero. If symbols are
present that have a zero value then the module resolver prints out
a message that these symbols are unresolved.

Use ERR_PTR to return an error code instead of 0. This is a bit awkward
since the addresses are handled as unsigned longs. So we need to convert
them everywhere.

Cc: Mathieu Desnoyers <[EMAIL PROTECTED]>
Cc: Kay Sievers <[EMAIL PROTECTED]
Signed-off-by: Christoph Lameter <[EMAIL PROTECTED]>

---
 kernel/module.c |   17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

Index: linux-2.6/kernel/module.c
===================================================================
--- linux-2.6.orig/kernel/module.c      2007-11-21 12:58:33.095608448 -0800
+++ linux-2.6/kernel/module.c   2007-11-21 13:00:30.199108674 -0800
@@ -285,7 +285,7 @@ static unsigned long __find_symbol(const
                }
        }
        DEBUGP("Failed to find symbol %s\n", name);
-       return 0;
+       return -ENOENT;
 }
 
 /* Search for module by name: must hold module_mutex. */
@@ -756,7 +756,7 @@ void __symbol_put(const char *symbol)
        const unsigned long *crc;
 
        preempt_disable();
-       if (!__find_symbol(symbol, &owner, &crc, 1))
+       if (IS_ERR_VALUE(__find_symbol(symbol, &owner, &crc, 1)))
                BUG();
        module_put(owner);
        preempt_enable();
@@ -902,7 +902,8 @@ static inline int check_modstruct_versio
        const unsigned long *crc;
        struct module *owner;
 
-       if (!__find_symbol("struct_module", &owner, &crc, 1))
+       if (IS_ERR_VALUE(__find_symbol("struct_module",
+                                               &owner, &crc, 1)))
                BUG();
        return check_version(sechdrs, versindex, "struct_module", mod,
                             crc);
@@ -955,7 +956,7 @@ static unsigned long resolve_symbol(Elf_
                /* use_module can fail due to OOM, or module unloading */
                if (!check_version(sechdrs, versindex, name, mod, crc) ||
                    !use_module(mod, owner))
-                       ret = 0;
+                       ret = -EINVAL;
        }
        return ret;
 }
@@ -1348,14 +1349,16 @@ static int verify_export_symbols(struct 
        const unsigned long *crc;
 
        for (i = 0; i < mod->num_syms; i++)
-               if (__find_symbol(mod->syms[i].name, &owner, &crc, 1)) {
+               if (!IS_ERR_VALUE(__find_symbol(mod->syms[i].name,
+                                                       &owner, &crc, 1))) {
                        name = mod->syms[i].name;
                        ret = -ENOEXEC;
                        goto dup;
                }
 
        for (i = 0; i < mod->num_gpl_syms; i++)
-               if (__find_symbol(mod->gpl_syms[i].name, &owner, &crc, 1)) {
+               if (!IS_ERR_VALUE(__find_symbol(mod->gpl_syms[i].name,
+                                                       &owner, &crc, 1))) {
                        name = mod->gpl_syms[i].name;
                        ret = -ENOEXEC;
                        goto dup;
@@ -1405,7 +1408,7 @@ static int simplify_symbols(Elf_Shdr *se
                                           strtab + sym[i].st_name, mod);
 
                        /* Ok if resolved.  */
-                       if (sym[i].st_value != 0)
+                       if (!IS_ERR_VALUE(sym[i].st_value))
                                break;
                        /* Ok if weak.  */
                        if (ELF_ST_BIND(sym[i].st_info) == STB_WEAK)
-
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